Question

gluten free: necessary for some, optional for others
gluten is a protein found in wheat, barley, rye, and sometimes oats-
ingredients often used in breads, pastas, and desserts. as a growing number
of people are choosing to avoid gluten in their diets, gluten-free products
have become increasingly popular in grocery stores and on restaurant
menus. after all, some people experience gas, diarrhea, or bloating after
ingesting gluten. for people whose symptoms are caused by mere
intolerance to the gluten protein or a wheat allergy, sidestepping gluten is a
lifestyle choice. but for those with a condition known as celiac disease,
avoiding gluten is a medical necessity.
what is the main focus of the text?
why people avoid gluten in their diets
a comparison of celiac disease and gluten intolerance
an overview of celiac disease

Explanation:

The text first introduces gluten, then mentions that as more people avoid gluten, gluten - free products are popular. It further explains that for some (with gluten intolerance or wheat allergy), avoiding gluten is a lifestyle choice, and for those with celiac disease, it's a medical necessity. So the main focus is on the reasons (lifestyle and medical) why people avoid gluten in their diets.

Answer:

why people avoid gluten in their diets